Dental cavity liners



of the filled tooth.

3,266,147 Patented August 16,1966

3,266,147 DENTAL CAVITY LINERS Henry M. Goldman, 1163 Beacon St.,Brookline, Mass. No drawing. Filed July 2, 1962, Ser. No. 207,040 7Claims. (Cl. 32-15) The present invention relates to liners for use inteeth cavities at fer they have been prepared to receive fillings.

The accepted practice is for a dentist to coat a tooth cavity With adental cement after it has been readied for filling, the coat beingeffective to block the effects of heat and cold on the filling frombeing a stimulant to the nerve It is also the practice to coat theprepared cavity with calcium hydroxide when the decay process is closeto the pulp of the tooth. This latter practice has the objectionablefeature that the coat does not show in an X-ray, a factor of particularimportance if a patient changes dentists. In that case and in theabsence of any record of previously performed work, the

.teeth are usually X-rayed. In a tooth filled in accordance with theabove summarized technique, the calcium hydroxide coat shows a void,and, as a consequence, the filling is usually removed to make sure thatthe apparent void does not represent decay.

The principal objectives of the present invention are to eliminate theabove referred to objectionable feature, to enable the dentist to applythe calcium hydroxide With maximum ease, convenience, and accuracy, andalso to provide an easy and effective method of lining a deep defectcaused by decay with the lining providing insulation against thermalchanges induced by a metal restoration. These objectives are attained byproviding a cavity liner in the form of a thin flexible sheet carryingfirst and second substances with each substance being distributedthroughout the area of the sheet so that they become a coat for thecavity when the liner is applied thereto. The first substance is calciumhydroxide and the second is opaque to X-rays and inert with respect tothe first substance.

In more detail, the sheet materials used are absorbent and of athickness to ensure that they can hold adequate amounts of bothsubstances. At the same time, it is essential that the liner be thinenough to make it easy to apply to a prepared cavity and to avoidinterference with the filling. Both objectives are met with a sheetthickness in the order of 1 mm. Surgical sponge material in sheets ofapproximately that thickness has proved satisfactory in use.

It is, of course, essential that the substance that is used as anindicator for X-ray photography be inert with respect to calciumhydroxide and those that meet that requirement are barium sulfate,bismuth sub-nitrate and bismuth sub-carbonate.

In order to ensure an effective calcium hydroxide coat, and at the sametime, safeguard against the appearance of any void should an X-ray besubsequently taken, both subs ances must be distributed throughout thearea of the sheet so that they become a coat for the cavity when theliner is applied thereto. This result is best achieved by mixing thesubstances together in water; the sheet is then saturated so that thesubstances are intimately mixed and evenly distributed providing, whenthe liner is applied, a coat for the prepared cavity that is both ablock against the effects of heat and cold and opaque with respect toX-rays.

Best results are obtained, as far as X-rays are concerned, when thesecond substance is a mixture of barium sulfate, bismuth sub-nitrate,and bismuth sub-carbonate, particularly when the three are mixedtogether in approximately equal parts.

In practice, it is preferred that the percentage by weight of calciumhydroxide to the percentage by weight of the indicator or indicators, bein the range of from 4060% to 60-40%. In practice, excellent results areattained when approximately equal parts by weight of both substances areused.

After the saturated sheet dries, it is ready for use. Once the cavity isreadied for filling, the dentist has but to cut from the sheet a piecethat will fit that particular cavity as a liner, and the filling maythen the completed, after that liner.=has been inserted in that cavity,with assurance that the calcium hydroxide coat is of maximumeffectiveness and will be opaque with respect to X-rays.

I claim:

1. A liner for a tooth cavity that has been prepared for filling andparticularly for use in place of a cement base where there aredeep-seated defectscaused by caries,

said liner comprising a thin, flexible sheet and first and secondintimately mixed substances carried by said sheet as a dry coating, eachbeing dry and distributed thereto, said first substance being calciumhydroxide and the second substance being opaque to X-rays and inert withrespect to the first substance and being at least one of the indicatorsfrom the group consisting of barium sulfate, bismuth sub-nitrate, andbismuth sub-carbonate.

2. A liner for a tooth cavity that has been prepared for filling andparticularly for use in place of a cement base where there aredeep-seated defects caused by caries, said liner comprising a thin, dryflexible sheet the thickness of said sheet being in the order of 1 mm.,and first and second intimately mixed substances carried by said sheetas a dry coating, each being dry and distributed throughout the area ofthe sheet so that each substance becomes a coat for the cavity when theliner is applied thereto, said first substance being calcium hydroxideand the second substance being opaque to X-rays and inert with respectto the first substance and being at least one of the indicators from thegroup consisting of barium sulfate, bismuth sub-nitrate, and bismuthsub-carbonate.

3. A liner for a tooth cavity that has been prepared for filling andparticularly for use in place of a cement base where there aredeep-seated defects caused by caries, said liner comprising a thin, dryflexible sheet of surgical sponge, the thickness of said sheet being inthe order of 1 mm., and first and second intimately mixed substancescarried by said sheet as a dry coating, each being dry and distributedthroughout the area of the sheet so that each substance becomes a coatfor the cavity when the liner is applied thereto, said first substancebeing calcium hydroxide and the second substance being opaque to X-raysand inert with respect to the first substance and being at least one ofthe indicators from the group consisting of barium sulfate, bismuthsub-nitrate, and bismuth subcarbonate.

4. A liner for a tooth cavity that has been prepared for filling andparticularly for use in place of a cement base where there aredeep-seated defects caused by caries, said liner comprising a thin, dryflexible sheet and first and second intimately mixed substances carriedby said sheet as a dry coating, each being dry and distributedthroughout the area of the sheet so that each substance becomes a coatfor the cavity when the liner is applied thereto, said first substancebeing calcium hydroxide and the second substance being opaque to X-raysand inert with respect to the first substance and comprising a mixtureof barium sulfate, bismuth sub-nitrate, and bismuth sub-carbonate.

5. A liner for a tooth cavity that has been prepared for filling andparticularly for use in place of a cement base where there aredeep-seated defects caused by caries, said liner comprising a thin, dryflexible sheet and first and second intimately mixed substances carriedby said sheet as a coating, each being dry and distributed throughoutthe area" of the sheet so that each substance becomes a coat for thecavity when the liner is applied thereto, said first substance beingcalcium hydroxide and the second substance being opaque to X-rays andinert with respect to the first substance and comprising a mixture ofequal parts of barium sulfate, bismuth sub-nitrate, and bismuthsub-carbonate.

6. A liner for a tooth cavity that has been prepared 'for filling andparticularly for use in place of a cement of barium sulfate, bismuthsub-nitrate, and bismuth subcarbonate.

7. A liner for a tooth cavity that has been prepared for filling andparticularly for use in place of a cement base where there aredeep-seated defects caused by caries, said liner comprising a thin dryflexible sheet and a mixture of approximately equal parts of first andsecond dry substances carried by said sheet, each being distributedthroughout the area of the sheet so that each substance becomes a coatfor the cavity when the liner is applied thereto, said first substancebeing calcium hydroxide and the second substance being opaque to X-raysand inert with respect to the first substance and comprising a mix tureof equal parts of barium sulfate, bismuth sub-nitrate, and bismuthsubcarbonate.

References Cited by the Examiner UNITED STATES PATENTS 2,516,438 7/1950Wheeler 10635 2,610,625 9/1952 Sifierd et a1 128296 2,644,232 7/1953Roubian 3215 2,899,362 8/1959 Sieger 16784 3,133,538 5/1964 Pratt et al128296 OTHER REFERENCES The Condensed Chemical Dictionary, sixthedition, Reinhold Pub. Corp., New York, page relied upon (1961).

Websters International Dictionary, 2nd ed. (1960), page 2434, cols. 2and 3, item 7 under sponge (as a noun).

ALEXANDER H. BRODMERKEL, Primary Examiner.

JOSEPH REBOLD, MORRIS LIEBMAN, Examiners.

H. MCCARTHY, I. B. EVANS, Assistant Examiners.

1. A LINER FOR A TOOTH CAVITY THAT HAS BEEN PREPARED FOR FILLING ANDPARTICULAR FOR USE IN PLACE OF A CEMENT BASE WHERE THERE ARE DEEP-SEATEDDEFECTS CAUSE BY CARRIES, SAID LINER COMPRISING A THIN, FLEXIBLE SHEETAND FIRST AND SECOND INTIMATELY MIXED SUBSTANCES CARRIED BY SAID SHEETAS DRY COATING, EACH BEING DRY AND DISTRIBUTED THROUGHT THE AREA OF THESHEET SO THAT EACH SUBSTANCE BECOMES A COAT FOR THE CAVITY WHEN THELINER IS APPLIED THERETO, SAID FIRST SUBSTANCE BEING CALCIUM HYDROXIDEAND THE SECOND SUBSTANCE BEING OPAQUE TO X-RAYS AND INERT WITH RESPECTTO THE FIRST SUBSTANCE AND BEING AT LEAST ONE OF THE INDICATORS FROM THEGROUP CONSISTING OF BARIUM SULFATE, BISMUTH SUB-NITRATE, AND BISMUTHSUB-CARBONATE.